From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 7/9] net: add skb_orphan_frags to copy aside frags with destructors Date: Sun, 6 May 2012 20:01:56 +0300 Message-ID: <20120506170156.GA30827@redhat.com> References: <20120503154142.GB27671@redhat.com> <20120503.135532.1038384417514973419.davem@davemloft.net> <20120503210826.GA30504@redhat.com> <20120504.025433.1474691040952890731.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ian.campbell@citrix.com, netdev@vger.kernel.org, eric.dumazet@gmail.com To: David Miller Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38223 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753920Ab2EFSUu (ORCPT ); Sun, 6 May 2012 14:20:50 -0400 Content-Disposition: inline In-Reply-To: <20120504.025433.1474691040952890731.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, May 04, 2012 at 02:54:33AM -0400, David Miller wrote: > From: "Michael S. Tsirkin" > Date: Fri, 4 May 2012 00:10:24 +0300 > > > Hmm we orphan skbs when we loop them back so how about reusing the > > skb->destructor for this? > > That's one possibility. > > But I fear we're about to toss Ian into yet another rabbit hole. :-) > > Let's try to converge on something quickly as I think integration of > his work has been delayed enough as-is. OK I tried doing this and I recalled why we do the copy with ubufs before clone: the problem is that shinfo is shared between skbs, so modifying frags like skb_orphan_frags does is racy. Stuck for now. So I have a question: how about reusing the TX_DEV_ZEROCOPY machinery for this, instead of frag destructors? Thanks, -- MST